Effect of Ultrasound on Adsorption and Desorption Processes

Abstract

The following paper is aimed at finding the effects of ultrasound on adsorption/desorption processes. Experiments concerning the ultrasonic power input indicate that particles absorb ultrasonic energy effectively if they are in resonance with the ultrasound. The ultrasonic energy is dissipated into heat. Hence, desorption processes are promoted. Desorption experiments at different frequencies show that neither particle oscillations nor cavitation effects are responsible for ultrasonically enhanced desorption processes for an adsorption system with surface diffusion as the rate-limiting step. Measured ultrasonic power distributions show that the ultrasonic field inside the adsorber is very inhomogeneous. With the temperature distribution inside the adsorber, the courses of concentration of ultrasonically enhanced desorption experiments can be explained by a hot-water desorption model. Thus, simulations substantiate the experimental results that thermal effects are responsible for ultrasonically enhanced desorption with the applied adsorption system.

Recovery, concentration and purification of phenolic compounds by adsorption: A review

“…The effects of ultrasounds on the adsorption and desorption of phenolics has been reported (Schneller and Yang, 2001;Li et al, 2002b;Breitbach et al, 2003). Upon sonication, attrition of ACs should be avoided by controlling frequency and intensity, whereas polymeric resins can withstand cavitational effects (Rege et al, 1998).…”

The influence of ultrasounds on the process of uranium desorption

“…In recent years the research regarding the application of ultrasounds in hydrometallurgy, in dissolution operations [24][25][26][27][28][29][30][31][32][33][34][35][36][37], ionic exchange [38][39][40][41][42][43][44][45][46][47], and solvent extraction [48][49][50][51][52][53] has expanded.…”

Treatment of refinery oily sludge using ultrasound, bio-surfactant, and advanced oxidation processes.

“…It has been reported that the destruction o f organic com pounds such as long-chain hydrocarbons was resulted from the production o f hydroxyl radicals (Feng and A ldrich, 2000). This usually occurs when the ultrasound is in the mid frequency from 200 to 400 kH z (Breitbach et al, 2003;Petrier and Francony, 1997). In this study, the condition for the production o f hydroxyl radicals was not reached at low frequency o f 20 kHz, thus there w as no significant destruction to change the PHC proportions in the recovered oil.…”

“…(Feng and Aldrich, 2000;M ason and Lorimer, 2002). It has been reported that the phenom ena o f ultrasonic cavitation could play a significant role in enhancing the desorption o f adsorbed molecules, and the effect o f cavitation depends on the size o f bubbles while m ore energy could be stored w ithin the bigger bubbles (Breitbach et al, 2003). In this study, the low frequency o f ultrasound (20 kH z) was applied.…”

“…In fact, for a multiphase system when solid phase exists, petroleum hydrocarbon molecules are either strongly adsorbed onto the surface o f solid particles or trapped inside the sediment matrix, and this would prevent the separation o f oil from the multiphase system. Previous studies (Feng and Aldrich, 2000;Breitbach et al, 2003;Hamdaoui et al, 2005) proved that ultrasound could effectively promote the desorption o f T able 3.3 Summary o f oil recovery results using different methods. …”